Smudge - I had the same situation last September with Ginger - he had a slight heart murmur, but other than that,the vet had said he seemed in good condition 3 weeks previously at his weigh in, my neighbour found him at the end of the street, and as he looked peaceful, I thought that it was something like his heart (wrong end of the street to be a car, he had only been out 10 mins and the neighbour hadn't heard anything), although it was hard as I will never know how he went, but it was a nice sunny day, and he went in his own time, which was totally like him - the irony is I took him off the streets, gave him a good 4 years, and he ended up going on the streets. It does still hurt 9 months later, my neighbour thought I was lucky cos I hadn't had to make that awful decision, but for me it was one of the hardest things I had gone through (but I always knew losing him would be harder than others), because I couldn't say goodbye to him, but I try and focus on the time we had, not how and when he went.